1. Field of the Invention
The present invention generally relates to the manufacture of printer cartridges. More particularly, the present invention relates to a system and method for suppression of air bubbles that form in the ink supply and nozzles of a printer cartridge while an article is ultrasonically welded to the printer cartridge.
2. Description of the Related Art
In the manufacturing of printer cartridges, and especially ink jet printer cartridges, a body of the cartridge is constructed with a fluid-tight interior of the cartridge open at the top end such that ink can fill and be held within the interior of the printer cartridge. Once the printer cartridge is filled with ink, a lid is typically ultrasonically welded to the top end of the printer cartridge to thus seal the interior of the printer cartridge except for an ink outlet on the bottom end of the printer cartridge through which the ink will eventually flow for printing. An example of a prior art system of ultrasonically welding a lid to a printer cartridge is illustrated in FIGS. 2 and 3.
As shown in FIG. 2, the printer cartridge 10 is fitted and secured within a recess 30 of a mounting fixture 24 and a welding horn 26 is fitted over a lid 18 to be welded the printer cartridge 10. The welding horn 26 typically is an ultrasonic welding device that welds the lid 18 to the printer cartridge 10. When inserted into the recess 30 of the mounting fixture 24, the bottom end 14 of the printer cartridge 10 creates an air space 32 and the nozzle plate assembly 28 is in contact with the air space 32 during the welding process. The nozzle plate assembly 28, as shown in detail in FIG. 3, typically includes a heating element 34 and a nozzle plate 36, through which ink flows from an ink supply 40 to an ink outlet 38, an example being a nozzle.
Consequently, as illustrated in FIG. 3, because the air space 32 surrounds outlet 38 the vibrations from the ultrasonic welding of the lid 18 cause air bubbles 42 to form in the ink nozzle 38 and ink supply 40. The air bubbles 42 cause problems in the continuity of the flow of ink from the ink nozzle 38 during printing, and possibly even cause interruption of ink flow during printing.
To prevent the air bubbles 42 from adversely affecting the manufactured printer cartridges, manufacturers purposely store the printer cartridges for a specific period of time prior to sale and usage of the printer cartridges. This storage period, sometimes for several days, allows the air bubbles 42 to work their way into the top of the ink supply 40, which thus minimizes the risk of the air bubbles 42 adversely affecting the ink flow of the printer cartridge 10. Additionally, the air bubbles 42 can dissolve back into the ink supply 40 over several days of storage of the printer cartridge 10. However, the time required for the printer cartridges to sit in inventory results in lost revenue for the manufacturer as the sale of the printer cartridges is delayed. Moreover, the cost for the physical space required to store the sitting printer cartridges is significant as such space must be at least of a commercial quality to provide an adequate environment for the storage.
Accordingly, a system and method that can minimize air bubbles in the ink nozzle and supply of the printer cartridge during the ultrasonic welding process would be advantageous as storage of the printer cartridges for air bubbles settling or dissolving into the ink would be unnecessary. Furthermore, such system and method would produce a better quality of printer cartridges as the ink flow would not be compromised by air bubbles. It is to the provision of such an improved system and method for suppressing bubble generation during ultrasonic welding on an ink-containing printer cartridge that the present invention is primarily directed.